1. Field of the Invention
The present invention relates to a compressed air starting device including a starter with a starter motor operated at least indirectly from a pneumatic pressure reservoir and a meshing unit controlled by a signal input.
2. Description of the Prior Art
Starting devices of this type make it possible to reliably mesh a starter pinion to the flywheel of an internal combustion engine and to reach the desired speed of the starter with relatively simple means.
However, a starter of this type requires that a starting valve be actuated during the entire starting procedure. This is true whether the starter is controlled manually or automatically, particularly electrically. The starter is separated from the compressed air source only after the starting valve has been brought into the closed position. The compressed air source may be via a compressed air supply or a compressed air reservoir.
Due to the continuous actuation of the starting valve during the starting phase, it is not possible to avoid in a reliable and satisfactory manner that excess speed of the starter occurs after the start of the internal combustion engine has occurred. This excess speed of the starter causes high wear and makes failure of the starter likely.
In a manually controlled starter, it may happen, for example, as the result of an oversight of the person operating the starter that the starter rotates with idle speed for a long period of time. This idle speed may become very high depending upon the level of pressure applied. As a result, the structural components remaining in engagement with the internal combustion engine must endure even higher speeds when overriding idle speed takes place.
In order to avoid these deficiencies, in automatic starters frequently a switching device is provided which operates in dependence upon the speed and which ends the starting procedure when a certain speed exceeding the starting speed has been reached. However, such a switching device not only makes the starter more complicated, it also does not provide reliable protection in the event of a malfunction or when the signal delays are too great.
Finally, in prior art starters, the compressed air reservoirs used in these starters are always dimensioned in such a way that several starting attempts are possible in the case of false starts without requiring an intermediate recharging of the compressed air reservoir. Generally, three to five starting attempts can be carried out. Therefore, it is desirable to keep the consumption of compressed air low.
It is, therefore, the primary object of the present invention to improve the compressed air starting device described above in such a way that the starting procedure can be automatically ended and excess speeds are avoided in a simple manner without requiring additional measuring or control device.